The positioning and deployment of medical devices within a target site of a patient is a common procedure of contemporary medicine. These devices, which may be implantable stents, chronic rhythm management leads, neuromodulation devices, implants, grafts, defibrillators, filters, catheters and other devices that may be deployed for short or sustained periods of time, may be used for many medical purposes. These can include the reinforcement of recently re-enlarged lumens, the replacement of ruptured vessels, and the treatment of disease, such as vascular disease by local pharmacotherapy, e.g., delivering therapeutic agent doses to target tissues while minimizing systemic side effects. The targeted delivery areas may include body lumens such as the coronary vasculature, esophagus, trachea, colon, biliary tract, urinary tract, prostate, brain, and the like.
Coatings may be applied to the surfaces of these medical devices to increase their effectiveness. These coatings may provide a number of benefits including reducing the trauma suffered during the insertion procedure, facilitating the acceptance of the medical device into the target site, and improving the post-procedure effectiveness of the device.
Coated medical devices may also provide for the localized delivery of therapeutic agents to target locations within the body. Such localized drug delivery avoids the problems of systemic drug administration, such as producing unwanted effects on parts of the body which are not to be treated, or not being able to deliver a high enough concentration of therapeutic agent to the afflicted part of the body. Localized drug delivery may be achieved, for example, by coating the entire outer surface of the medical device or just those portions of the medical device that directly contact the desired treatment site, such as the inner vessel wall. This drug delivery may be intended for short and/or sustained periods of time.